mineral

Fluorite

Calcium Fluoride (CaF2)

Hardness: 4 on Mohs scale; Color: typically green, purple, yellow, or clear; Luster: Vitreous (glassy); Crystal structure: Isometric (cubic or octahedral); Cleavage: Perfect octahedral in four directions; Specific gravity: 3.175–3.184.

Hardness: 4 on Mohs scale
Color: typically green, purple, yellow, or clear
Luster: Vitreous (glassy)

Identified April 4, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal activity, often in veins or as a gangue mineral in metallic ores. It can form in various temperatures and is found worldwide in sedimentary and igneous environments.

Uses & applications

Used as a flux in steel making, in the production of hydrofluoric acid, in high-performance optical lenses (due to low dispersion), as a gemstone, and in ornamental carvings.

Geological facts

Fluorite is the most colorful mineral in the world. It was the original source for the discovery of fluorescence, as many specimens glow under ultraviolet light. It is also the state mineral of Illinois.

Field identification & locations

Identify by its characteristic 4-way octahedral cleavage, glass-like luster, and relative softness (it can be scratched by a steel knife but can scratch a copper coin). Common locations include China, Mexico, South Africa, and the UK.